1. Field of the Invention
The invention relates to a tank cap with free travel to close a fuel tank of a motor vehicle, which can be screwed on a filler neck of the fuel tank so that it seals via rotational movement around a rotational axis and features an inner closure body and a cap body, which is pivoted on the closure body around a free travel angle delimited by a first limit stop and a second limit stop.
2. Description of the Related Art
A tank cap is known from German printed patent specification 199 10 684, which corresponds to Patent No. U.S. Pat. No. 6,209,746. In the case of this known tank cap, the free travel is provided to prevent the cap from being unintentionally rotated by sheet metal edges that move in the case of an accident and being opened as a result. For this purpose the cap body is rotatable relative to the closure body, whereby a carrier of the one component is moved against a first and a second limit stop of the respective other component so that force is generated after the free travel is overcome. A spring, which holds the tank cap in a defined home position, can be arranged between the two components to guarantee that a free travel angle must always be overcome in the opening rotational direction before the generation of force becomes active. Another holding agent can be provided as an alternative to a spring, for instance an easy locking connection, which holds the tank cap at the second limit stop after it is screwed in and thus the locking force must be overcome in order to unscrew it.
In addition to these functional components, ventilation is normally provided in the interior of the tank cap, which is realized via a spring-loaded valve. In addition, most of the time known tank cap features a ratchet connection that guarantees a limitation of the torque in the closing direction so that overturning the screw connection or the bayonet connection in the filler neck and thus damage to the fastening mechanism can be avoided.
The known tank caps have the disadvantage that the limit stops must be realized using pins or comparable components that can only be produced very expensively with sufficient accuracy. Moreover, there exists the danger that once the pin lengths exceed a certain extent the limit stops cannot withstand the mechanical stress of the torque transmission and thus an error can occur. Finally, in most cases the known tank cap can be put together incorrectly so that a malfunction occurs from the limit stops not being arranged at the planned for positions, because the closure body relative to the cap body was put together rotationally misaligned relative to the target position for example.
Hence, those skilled in the art have recognized a need for a tank cap with free travel that can be mounted easily and is cost-effective to manufacture, whereby reliable force transmission from the cap body to the closure body remains guaranteed. The invention fulfills these needs and others.